Feel I need to clarify my fix to the "eBay/ASZ redirection problem" discussed in my last post.
Adding your domain name to your DNS search path will stop your DNS resolver from asking the "au.com.au" and "com.com.au" name servers for "google.com.au.com.au". So you shouldn't get "Welcome to ASZ.COm.Au" or be redirected to eBay or other unexpected behaviour.
What you'll get instead is "site not found". That's what I mean by a partial fix. If your ISPs name server is losing DNS responses (or is too slow to return them) then you'll still have problems: namely you'll get an error message when you try and visit some sites. However clicking "Refresh" or "Reload" will generally solve that problem. Once your at the site the address will be in your resolver's cache so things will be stable for a while.
Meanwhile I've written to the auDA guys asking for their opinion on defining DNS entries for other peoples domain names as sub-domains of yours.